There have been a number of important developments in U.S. intellectual property law since the third edition of Understanding Intellectual Property Law was published. Congress enacted the Defend Trade Secrets Act of 2016 to provide a federal civil cause of action for misappropriation of trade secrets for the first time. It also enacted the Music Modernization Act of 2018, which extends the compulsory license for musical works by creating a blanket license for digital music providers and provides federal protection to sound recordings fixed before February 15, 1972. And, of course, courts continue to work through the implications of earlier statutory revisions, such as the landmark America Invents Act of 2011. The Supreme Court has remained active in reviewing intellectual property cases during the past four years, deciding eighteen patent cases, four copyright cases, and five trademark cases. In addition, the federal Courts of Appeals decided more than 1000 patent cases, 230 copyright cases, and nearly 300 trademark and false advertising cases during that time. Having been updated to reflect this new material, the fourth edition of Understanding Intellectual Property Law covers all of the intellectual property areas and issues likely to be addressed in an intellectual property survey course.